Wiring substrate and electronic device

ABSTRACT

A wiring substrate includes a plurality of electrode terminals, to which external connection terminals of an electronic component are coupled, arranged in a row on one principal surface thereof, wherein the electrode terminals each include: a first linear portion; a second linear portion extending from an end of the first linear portion in a direction different from a direction of the first linear portion; and a bent portion that is a part where the first linear portion and the second linear portion are connected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2007-61531, filed on Mar. 12,2007, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a wiring substrate and an electroniccomponent mounting structure.

BACKGROUND

Japanese Patent Laid-Open No. 5-308184 discloses a structure of acircuit board with a solder layer provided on pads constituting aconductive layer, in which the width of a part in the longitudinaldirection of each pad is widened, and a solder-banked portion having asolder layer thickness that is larger than those of the other portionsis formed on the widened portion.

Japanese Patent Laid-Open No. 6-216507 discloses a structure in whichthe width of a pad is widened in its middle portion, the center in thelength direction of the pad-widened portion is positioned within therange of the length of a flat portion of a component lead, the length ofthe pad-widened portion is longer than the length of the flat portion ofthe component lead, and a solder-banked portion having a thicknesslarger than those of the other portions is formed on the pad-windedportion.

Japanese Utility Model Registration No. 3115062 discloses a circuitpattern formed by selectively coating a wiring pattern with a solderresist, in which the exposed wiring pattern areas are used aselectrodes. In this circuit pattern, each electrode is formed so thatonly one portion in the longitudinal direction of the electrode has amaximum width.

Japanese Patent Laid-Open No. 2000-77471 discloses a structure in whicha conductor pattern is formed by a wiring pattern and connection pads towhich bumps of a semiconductor element is connected, and the width ofeach connection pad is larger than the width of each wiring patternline.

Japanese Patent Laid-Open No. 2004-40056 discloses a structure in whicha plurality of wiring pattern lines are arranged in a row on thesubstrate, first linear portions of the wiring pattern lines are formedin parallel or nonparallel to each other, and second linear portions ofthe wiring pattern lines are formed on the same straight line.

However, in recent years, semiconductor elements mounted on wiringsubstrates have been increasingly downsized and have had a larger numberof terminals. Also, there has been the demand for high-density mountingof such a semiconductor element on a wiring substrate. Narrowing thepitch of protruded external connection terminals formed on thesemiconductor element in order to meet such demand makes the spacebetween the widened portions of electrodes (conductive layer) providedadjacent to each other on the wiring substrate smaller in the approachesin the above-mentioned patent documents.

Accordingly, when mounting the semiconductor element on the wiringsubstrate, the conductive member provided on the widened portion may runoff between the adjacent connection portions formed by the protrudedexternal connection terminals of the semiconductor element and theconductive layer of the wiring substrate. Consequently, between thoseconnection portions, short-circuiting or current leakage may occur,lowering the reliability of electric connection between the protrudedexternal connection terminals of the semiconductor element and theelectrodes (conductive layer) of the wiring substrate.

Also, in the structure disclosed in Japanese Patent Laid-Open No.2004-40056, second linear portions of adjacent wiring pattern lines arearranged on the same straight line in a direction of the wiring patternline row extending. Accordingly, it is difficult to narrow the pitchbetween the wiring pattern lines.

SUMMARY

According to an aspect of an embodiment, a wiring substrate includes aplurality of electrode terminals, to which external connection terminalsof an electronic component are coupled, arranged in a row on oneprincipal surface thereof, wherein the electrode terminals each include:a first linear portion; a second linear portion extending from an end ofthe first linear portion in a direction different from a direction ofthe first linear portion; and a bent portion that is a part where thefirst linear portion and the second linear portion are connected.

According to an another aspect of an embodiment, an electronic deviceincludes a wiring substrate including a plurality of electrode terminalsarranged in a row on one principal surface thereof; and an electroniccomponent mounted on the plurality of electrode terminals via aconductive member, wherein: the electrode terminals each includes afirst linear portion, a second linear portion extending from an end ofthe first linear portion in a direction different from a direction ofthe first linear portion, and a bent portion that is a part where thefirst linear portion and the second linear portion are connected; andexternal connection terminals of the electronic component are coupled tothe bent portions of the electrode terminals via the conductive member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a semiconductor device according toa first embodiment;

FIG. 2 is a plain view of a planar configuration of the part circled bydashed line A in the wiring substrate shown in FIG. 1;

FIG. 3 is a diagram illustrating a cross-section taken along line X-X inthe wiring substrate shown in FIG. 2;

FIG. 4 is a cross-sectional view illustrating a state in which aconductive member is coated on electrode terminals on the wiringsubstrate shown in FIG. 3;

FIGS. 5A to 5C are diagrams for explaining the thickness of a conductivemember provided on a bent portion of an electrode terminal on a wiringsubstrate, and the thicknesses of conductive members provided on a firstlinear portion and a second linear portion;

FIGS. 6A and 6B are cross-sectional views (part 1) for explaining aprocess of mounting a semiconductor element on the wiring substrateshown in FIG. 1;

FIGS. 7A and 7B are cross-sectional views (part 2) for explaining aprocess of mounting a semiconductor element on the wiring substrateshown in FIG. 1;

FIG. 8 is a partial plain view of electrode terminals on a wiringsubstrate according to a second embodiment;

FIG. 9 is a partial plain view of electrode terminals on a wiringsubstrate according to a third embodiment;

FIGS. 10A and 10B are partial plain views of arrangement structures ofexternal connection terminal pads and protruded external connectionterminals of a semiconductor element to be mounted on the wiringsubstrate shown in FIG. 8 or FIG. 9;

FIG. 11 is a partial plain view of electrode terminals on a wiringsubstrate according to a fourth embodiment;

FIG. 12 is a partial plain view of an arrangement structure of externalconnection terminal pads and protruded external connection terminals ona semiconductor element to be mounted on the wiring substrate shown inFIG. 11;

FIG. 13 is a cross-sectional view of a structure in which thesemiconductor element shown in FIG. 12 is mounted on the wiringsubstrate shown in FIG. 11;

FIG. 14 is a partial plain view of electrode terminals on a wiringsubstrate according to a fifth embodiment;

FIG. 15 is a partial plain view of an arrangement structure of externalconnection terminal pads and protruded external connection terminals ofa semiconductor element to be mounted on the wiring substrate shown inFIG. 14; and

FIG. 16 is a cross-sectional view of a structure in which thesemiconductor element shown in FIG. 15 is mounted on the wiringsubstrate shown in FIG. 14.

DETAILED DESCRIPTION First Embodiment

Hereinafter, a first embodiment is described.

Although a semiconductor mounted on a wiring substrate according to thefirst embodiment is described as an electronic component, the electroniccomponent is not limited to the semiconductor element, and it may be asemiconductor device with a semiconductor element encapsulated by aresin, or a passive element, etc.

FIG. 1 is a cross-sectional view of a semiconductor device 10 accordingto the first embodiment. As shown in the Figure, in the semiconductordevice 10, a semiconductor integrated circuit element (hereinafterreferred to the “semiconductor element”) 12 is mounted by means of aflip-chip (face-down) method on one principal surface (top surface) of awiring substrate 11.

The wiring substrate 11 has, as its base material, an organic insulatingmaterial such as a glass epoxy resin, a glass-BT (bismaleimide triazine)or polyimide, or an inorganic material such as ceramic or glass. Awiring layer including copper (Cu) is selectively provided on a surfaceor in an inside of the wiring layer. The wiring substrate 11 may also bereferred to an interposer or a support substrate.

On that principal surface of the wiring substrate 11 on which thesemiconductor element 12 is mounted, a conductive layer 13 connected tothe wiring layer is selectively provided. The wiring substrate 11 isselectively coated by a solder resist layer (insulating resin film) 15,excluding the parts to which external connection terminals 14 of thesemiconductor element 12 are connected and the areas around the parts.In other words, the solder resist layer 15 selectively coats theconductive layer 13. The solder resist includes a resin such as an epoxyresin, an acrylic resin or a polyimide resin, or a mixture resinthereof, etc.

As a result, parts of the conductive layer 13 are exposed as electrodeterminals 16, through openings provided in the solder resist layer 15.The solder resist layer 15 defines the areas of the conductive layer 13connected to the semiconductor element 12, that is, the portions wherethe electrode terminals 16 are exposed.

Also, on the other principal surface (rear surface) of the wiringsubstrate 11, a conductive layer is selectively provided. On theconductive layer, a plurality of external connection terminals, such assolder-based spherical electrode terminals, are provided. In the firstembodiment, those external connection terminals are not shown.

The semiconductor element 12 includes semiconductor substrate 17composed of semiconductor such as silicon (Si), or a semiconductorcompound such as gallium arsenide GaAs). Electronic circuits are formedon one principal surface of the semiconductor substrate 17 by means of aknown semiconductor manufacture process.

For the semiconductor element 12, the showing of active elements such astransistors, and/or passive elements such as capacitative elements,formed in the semiconductor substrate 17, and a multilayered wiringlayer and/or a rewiring layer formed on the one principal surface of thesemiconductor element 12 is omitted.

On the one principal surface of the semiconductor substrate 17, externalconnection terminal pads 18 are arranged in rows around the electroniccircuit portions. The protruded external connection terminals 14 arearranged on the respective external connection terminal pads 18.

The external connection terminal pads 18 are formed of aluminum (Al),copper (Cu) or an alloy thereof, etc. Each protruded external connectionterminal 14 is formed by means of, for example, what is calledball-bonding method, and has a base portion including a gold (Au) ballfixed and adhered to an external connection terminal pad 18, and aprotruded portion projecting from the base portion. The base portion andthe protruded portion are integrally formed. Also, a top of theprotruded external connection terminal 14 is subjected to planarizationprocessing as needed.

On a surface (the top layer) of the external connection terminal pads18, a gold (Au) layer may be formed in advance by means of electrolyticplating or vapor deposition, etc.

The protruded external connection terminals 14 may be formed of, forexample, copper (Cu), or an alloy of copper (Cu) and gold (Au), orsolder, etc.

At least protruded portions of the protruded external connectionterminals 14 on the semiconductor element 12, and the correspondingelectrode terminals 16 on the wiring substrate 11 are coated in commonby a conductive member 19 having remelting capability and aremechanically and electrically connected to each other.

As a material of the conductive member 19, solder is used. Solder hasremelting capability, but exhibits high fluidity when it is melted as aresult of heating, compared to other conductive materials havingremelting capability such as a conductive resin adhesive, and isfavorable for a material for the conductive member 19. Also, when usingsolder as the conductive member 19, a solder material for pre-coatingwiring substrate 11 can be used as the conductive member 19. This isconvenient because a solder pre-coating technique can be used, and also,expensive material costs can be avoided.

Between the semiconductor element 12 mounted and fixed in a flip-chip(face-down) method on the one principal surface of the wiring substrate11 as described above, and the one principal surface of the wiringsubstrate 11, an underfill material 20 is filled. For the underfillresin material 20, a thermosetting adhesive, such as an epoxy resin, apolyimide resin, or an acrylic resin, etc. is used.

A structure of the electrode terminals 16 is described with reference toFIGS. 2-4.

FIG. 2 is a planar view of the inside portion indicated using dashedline A in FIG. 1. In the Figure, the semiconductor element 12 and theunderfill material 20 are omitted. FIG. 3 is a cross-sectional view ofthe wiring substrate 11 along line X-X in FIG. 2.

As shown in FIG. 2, the solder resist layer 15 is provided so that itselectively coats the plurality of conductive layers 13 arranged on theone principal surface of the wiring substrate 11. The parts of theconductive layers 13 not coated by the solder resist layer 15 areexposed as the electrode terminals 16.

In the Figure, dashed line B indicates an outer peripheral edge of thesemiconductor element 12 to be mounted by means of flip-chip bonding onthe wiring substrate 11, and dashed line circle C indicates a connectionpart of an electrode terminal 16 to which a protruded externalconnection terminal 14 of the semiconductor element 12 is connected. Inother words, the semiconductor element is positioned on the right sideof dashed line B.

Each electrode terminal 16 includes a first linear portion 16-1, asecond linear portion 16-2 extending from an end of the first linearportion 16-1 in a direction that is different from the first linearportion 16-1, and a bent portion 16-3 where the first linear portion16-1 and the second linear portion 16-2 are connected. First linearportions 16-1 adjacent to each other are arranged in parallel to eachother. Also, second linear portions 16-2 adjacent to each other arearranged in parallel to each other.

The first linear portion 16-1 and the second linear portion 16-2 areconnected at a predetermined angle (obtuse angle in the firstembodiment). The bent portion 16-3 is bended in a V-letter shape. Aprotruded external connection terminal 14 of the semiconductor element12 is connected to the bent portion 16-3.

The bent portions 16-3 of electrode terminals 16 are arranged in thesame straight line, and the arrangement corresponds to the arrangementof the external connection terminal pads 18 of the semiconductor element12.

FIG. 4 shows a state in which the electrode terminals 16 are coated bythe conductive member 19.

As described above, the conductive member 19 having remelting capabilityis arranged on surfaces of the electrode terminals 16, and the protrudedexternal connection terminals 14 of the semiconductor element 12 arefixed and connected thereto via the conductive member 19.

As shown in FIG. 4, the thickness of the conductive member 19 disposedon the bent portion 16-3 of the electrode terminal 16 is greater thanthat of each conductive member 19 disposed on the first linear portion16-1 and the second linear portion 16-2.

The reason why a difference in thickness of the conductive member 19occurs in one electrode terminal 16 will be explained with reference toFIG. 5. FIG. 5A shows one of the electrode terminals 16, FIG. 5B is across-sectional view of the bent portion 16-3 of the electrode terminal16 (cross-sectional view along line a-a in FIG. 5A), and FIG. 5C is across-sectional view of one linear portion 16-2 of the electrodeterminal 16 (cross-sectional view along line b-b in FIG. 5A). FIG. 5Cshows the cross-section of one linear portion 16-2, but the other linearportion 16-1 has a similar cross-sectional structure.

Here, it is assumed that the surface tension of the conductive member 19is γ, and that the external air pressure is Po. It is also assumed thatthe internal pressure of the conductive member 19 in the cross-sectionalong line a-a in FIG. 5A is Pa, and that the internal pressure of theconductive member 19 in the cross-section along line b-b in FIG. 5A isPb. It is further assumed that the curvature radius of the conductivemember 19 in the cross-section along line a-a in FIG. 5A is Ra, and thecurvature radius of the conductive member 19 in the cross-section alongline b-b in FIG. 5A is Rb.

Expressions (1) and (2) can be formulated by Laplace's theorem relatedto surface tension:

ΔPa=Po−Pa=2γ/Ra  Expression (1); and

ΔPb=Po−Pb=2γ/Rb  Expression (2).

When the conductive member 19 is melted and enters an equilibrium stateas a result of its surface tension being exerted, the internal pressurePa of the conductive member 19 in the bent portion 16-3 and the internalpressure Pb of the conductive member 19 in the second linear portion16-2 are equal to each other, and accordingly, expression (3) can beobtained from expressions (1) and (2):

Rb=Ra  Expression (3).

Meanwhile, the following relational expression (4) can be formulated fora flexion angle θ of the bent portion 16-3, the width (maximum width) Daof the bent portion 16-3, and the width Db of the second linear portion16-2:

Da=[1/{sin(0.5θ)}]×Db  Expression (4).

In this expression, the flexion angle θ of the bent portion 16-3 is 0degrees<θ<180 degrees, and in this range, the following relationalexpression (5) can be obtained from expression (4):

Da>Db  Expression (5).

Based on expressions (3) and (5) above, when the conductive member 19 isin an equilibrium and melted state, the following relational expression(6) can be obtained for the thickness Ha of the conductive member 19 inthe cross-section of the bent portion 16-3 (cross-section along line a-aof FIG. 5A), and the thickness Hb of the conductive member 19 in thecross-section of the second linear portion 16-2 (cross-section alongline b-b of FIG. 5A):

Ha>Hb  Expression (6).

As described above, the height (thickness) of the conductive member 19on the bent portion 16-3 of the electrode terminal 16 becomes greatcompared to the first linear portion 16-1 and the second linear portion16-2.

Also, since the influence of gravity becomes smaller as the electrodeterminal 16 is miniaturized, the influence of gravity exerted on theconductive member 19 is ignored in the explanation of expressions (1) to(6) for easy understanding of the action principle. Furthermore, for theconductive member 19, one that can be applied only to the top surfaceportion of the electrode terminal 16 and has a constant curvature radiusis used.

As described above, as a result of the effective width of the electrodeterminal 16 varying, the thickness (height) of the conductive member 19disposed on the surface of the electrode terminal 16 also varies. Inother words, as shown in FIG. 4, after the conductive member 19 isdisposed on the electrode terminal 16, it is heated to enhance itsfluidity, and the conductive member 19 that has become liquid has themaximum thickness at the bent portion 16-3 due to its surface tension.

As a result of the temperature of the conductive member 19 being loweredor the conductive member 19 being solidified, the conductive member 19is formed so that the conductive member 19 has a great thickness at thebent portion 16-3 compared to the first linear portion 16-1 and thesecond linear portion 16-2.

In other words, when forming the conductive member 19 on the electrodeterminal 16 by means of coating, the coating thickness (height) of theconductive member 19 at the bent portion 16-3, which is the part of theelectrode terminal 16 to which a protruded external connection terminal14 of the semiconductor element 12 is connected, can be formed to bethick (high).

As described above, in the first embodiment, when connecting theprotruded external connection terminals 14 of the semiconductor element12 to the electrode terminals 16 of the wiring substrate 11, aconductive member 19 having a sufficient amount (thickness) can bedisposed, thereby non-uniformity of the heights of the protrudedexternal connection terminals 14 and/or warpage of the wiring substrate11 can be absorbed. Consequently, when mounting the semiconductorelement 12 on the wiring substrate 11 by means of flip-chip bonding, itsconnection stability (yield) can be enhanced.

Also, by making the flexion angle of the bent portion 16-3 of theelectrode terminal 16 to be an acute angle, the height of the conductivemember 19 at the relevant local portion 16-3 can be made greater, butthe flexion angle can be arbitrarily selected based on the width ormutual pitch of the electrode terminals, etc.

As described above, the conductive member 19 is formed having a greatthickness at the bent portion 16-3 of the electrode terminal 16.Accordingly, even when the pitch of the protruded external connectionterminals 14 of the semiconductor element 12 is narrowed, and the widthof the electrode terminals 16 of the wiring substrate 11 is narrowed inresponse to this, a great connection strength can be achieved for theconnection with the protruded external connection terminals 14.

Also, the non-uniformity of the heights of the protruded externalconnection terminals 14 of the semiconductor element 12, or warpage ofthe wiring substrate 11 is absorbed, ensuring reliable electricconnection between the protruded external connection terminals 14 of thesemiconductor element 12 and the bonding electrodes 16 of the wiringsubstrate 11.

Meanwhile, the plurality of electrode terminals 16 are arranged withtheir first linear portions 16-1 in parallel to each other, and alsowith the their second linear portion 16-2 in parallel to each other, soa high arrangement density can be obtained for the electrode terminals16 on the wiring substrate 11.

Also, even though the arrangement pitch of the protruded externalconnection terminals 14 of the semiconductor element 12 is narrowed, thewidth of the electrode terminals 16 on the wiring substrate 11 is alsominiaturized in response to this, short-circuiting between the electrodeterminals or current leakage can be prevented when mounting thesemiconductor element 12 on the wiring substrate 11 by means offlip-chip bonding, and consequently, a highly-reliable mountingstructure can be achieved.

Next, a process of mounting the semiconductor element 12 on the wiringsubstrate 11 is described with references to FIGS. 6 and 7.

First, the wiring substrate 11 mounted and fixed on a boding stage (notshown) and the semiconductor element 12 sticking to and held by asucking tool 21 are made to face each other (see FIG. 6A).

The wiring substrate 11, as described above, has, as its base material,an organic insulating material such as a glass epoxy resin, a glass-BT(bismaleimide triazine) or polyimide, or an inorganic material such asceramic or glass, and on a surface thereof or in the inside thereof, awiring layer comprising copper (Cu), etc., is selectively provided.

On one (top) principal surface of the wiring substrate 11, a conductivelayer 13 connected to the wiring layer is provided. The conductive layer13 is selectively coated by a solder resist layer (insulating resinfilm) 15, and at openings of the solder resist layer 15, a plurality ofelectrode terminals 16 are exposed.

The electrode terminals 16 are formed by means of what is calledphoto-etching, or selective plating, etc., and formed into a patternaccording to the idea of the first embodiment as shown in FIG. 2. Inother words, each electrode terminal 16 includes a first linear portion16-1, and a second linear portion 16-2, and the first linear portion16-1 and the second linear portion 16-2 are connected via a bent portion16-3 having a predetermined angle.

Meanwhile, the semiconductor element 12 has protruded externalconnection terminals 14 on external connection terminal pads 18 arrangedon a principal surface of a silicon (Si) semiconductor substrate 17.

The external connection terminal pads 18 are generally formed ofaluminum (Al), copper (Cu) or an alloy thereof, etc. Each protrudedexternal connection terminal 14 is integrally formed having a baseportion formed by a gold (Au) ball being fixed and connected to asurface of an external connection terminal pad 18 by means of what iscalled ball-bonding, and a protruded portion comprising a projectingpart on the base portion.

Also, the top of the protruded external connection terminal 14 may besubjected to planarization processing.

For forming the protruded external connection terminal 14 on the surfaceof the external connection terminal pad 18, a method in which gold (Au),copper (Cu) or nickel (Ni), etc., is deposited by means of electrolyticplating or non-electrolytic plating may be employed.

Furthermore, on the exposed surface (top layer) of the externalconnection terminal pad 18, a gold (Au) layer may be formed by means ofelectrolytic plating or vapor deposition, etc.

Meanwhile, on each electrode terminal 16 of the wiring substrate 11, aconductive member 19 formed of solder based on, for example, tin (Sn) isapplied and formed in advance by means of printing, plating or vapordeposition and reflow, etc.

Here, the thickness (height in the vertical direction) of the conductivemember 19 provided on the bent portion 16-3 of the electrode terminal16, as described above, is greater than the thickness of each conductivemember 19 provided on the first linear portion 16-1 and the secondlinear portion 16-2.

The external connection terminals 14 of the semiconductor element 12having the above-described electrode structure are aligned with the bentportions 16-3 of the electrode terminals 16 of the wiring substrate 11so as to face them.

The above sucking tool 21 is pre-heated to a temperature equal to orexceeding the melting point of the conductive member 19 (e.g. 180° C. to260° C.) using heating means (not shown).

In that state, the sucking tool 21 that sucks and holds thesemiconductor element 12 is lowered to make the protruded externalconnection terminals 14 of the semiconductor element 12 in contact withthe conductive member 19 covering surfaces of the electrode terminals 16of the wiring substrate 11, and then weight is applied by the suckingtool 21 to make the conductive member 19 melt.

As a result, at least the projecting portions of the protruded externalconnection terminals 14 of the semiconductor element 12 are coated bythe conductive member 19, and the protruded external connectionterminals 14 of the semiconductor element 12 and the electrode terminals16 of the wiring substrate 11 are connected via the conductive member 19(see FIG. 6B).

Also, it is possible to increase the temperature of the conductivemember 19 in a short period of time by pre-heating the bonding stage toa temperature of around 50° C. to 100° C. to pre-heat the wiringsubstrate 11.

As described above, the protruded external connection terminals 14 ofthe semiconductor element 12 are connected and fixed to the bentportions 16-3 of the electrode terminals 16 on the wiring substrate 11,and the semiconductor element 12 is mounted on the wiring substrate 11,and then, an underfill material 20 such as a thermosetting adhesivecomprising an epoxy resin, a polyimide resin, or an acrylic resin, etc.,is filled between the wiring substrate 11 and the semiconductor element12 (see FIG. 7A).

The underfill material 20 is supplied via a nozzle 22.

As described above, on the one principal surface of the wiring substrate11, the semiconductor element 12 is mounted and fixed by means of aflip-chip (face-down) method, and the protruded external connectionterminals 14 of the semiconductor element 12 and the correspondingelectrode terminals 16 of the wiring substrate 11 are mechanically andelectrically connected via the conductive member 19 (see FIG. 7B).

Subsequently, on the other principal surface (lower surface) of thewiring substrate 11, external connection terminals such as solder-basedspherical electrode terminals are arranged (not shown) to form asemiconductor device 10.

According to the first embodiment, the configuration of the electrodeterminals on the wiring substrate, and the arrangement structure of theexternal connection terminals of the semiconductor element are notlimited to the structures shown in FIG. 2, but structures like thosedescribed in the following modifications can also be employed.

Second Embodiment

FIG. 8 shows the configuration of electrode terminals on a wiringsubstrate according to a second embodiment. In the Figure, dashed line Bindicates an outer peripheral edge of a semiconductor element to bemounted on a wiring substrate 81, and dashed line circle C indicates apart in which a protruded external connection terminal of thesemiconductor element is connected to an electrode terminal of thewiring substrate. In other words, the semiconductor element ispositioned on the right side of dashed line B.

In the second embodiment, also, a plurality of electrode terminals 85arranged on the wiring substrate 81 each include a first linear portion85-1 and a second linear portion 85-2 that have a fixed width and areconnected to each other. The first linear portion 85-1 and the secondlinear portion 85-2 are connected via a bent portion 85-3 constitutingan obtuse angle, and extend in directions that are different from eachother.

In such configuration, the first linear portion 85-1 of each electrodeterminals 85 has a relatively-short linear shape (strip-shape), and aplurality of first linear portions 85-1 are arranged in a directionalong the outer peripheral edge of the semiconductor element in parallelto each other.

Meanwhile, each second linear portion 85-2 is arranged by connecting toone end of a first linear portion 85-1 via a bent portion 85-3, and suchbent portions 85-3 arranged on the plurality of first linear portions85-1 with their positions alternately changed, and as a result, thesecond linear portions 85-2 extend in different directions (lowerleftward and upper rightward directions in the shown structure) forevery other first linear portion 85-1.

In other words, one ends and the other ends of the plurality of thefirst linear portions 85-1 arranged in a direction along the outerperipheral edge of the semiconductor element are alternately selected,and from those selected ends, the second linear portions 85-2 extend.

Accordingly, the bent portions 85-3, that is, the parts to which theexternal connection terminals of the semiconductor element are connectedare alternately provided having different distances from the outerperipheral edge of the semiconductor element. Consequently, it ispossible to effectively increase the distance between adjacent bentportions 85-3, and to effectively increase the pitch of the externalconnection terminals of the semiconductor element that are connected tothe bent portions 85-3 in a direction along the outer peripheral edge ofthe semiconductor element. Also, the second linear portions 85-2extending in the same direction are arranged so that they are inparallel to each other.

Third Embodiment

FIG. 9 shows the configuration of electrode terminals of a wiringsubstrate according to a third embodiment. In the Figure, dashed line Bindicates an outer peripheral edge of a semiconductor element to bemounted on a wiring substrate 91. In other words, the semiconductorelement is positioned on the right side of dashed line B. Also, a partwhere a protruded external connection terminal of the semiconductorelement is connected to an electrode terminal on the wiring substrate isindicated by a dashed line circle.

In the third embodiment, also, a plurality of electrode terminals 95arranged on the wiring substrate 91 each include a first linear portion95-1 and a second linear portion 95-2 that have a fixed width and areconnected to each other. The first linear portion 95-1 and the secondlinear portion 95-2 are connected via a bent portion 95-3 constitutingan obtuse angle, and extend in directions that are different from eachother.

In such configuration, the first linear portions 95-1 of the electrodeterminals 95 have a relatively-short linear shape (strip-shape) as thosein the second embodiment above do. They are arranged with inclinationsin two rows in a direction along the outer peripheral edge of thesemiconductor element, and in each row, they are arranged in parallel toeach other.

The first linear portions 95-1 of the electrode terminals 95 arranged intwo rows have different inclination directions for the respective rows,and ends of the first linear portions 95-1 of the electrode terminals 95constituting one of the rows are arranged near ends of the first linearportion 95-1 of the electrode terminals 95 constituting the other of therows.

Meanwhile, the second linear portions 95-2 are arranged so that they areconnected to the other ends, i.e., the ends on the side far from theother row, of the first linear portions 95-1 via the bent portions 95-3.The second linear portions 95-2 extend in directions going away from therows.

In other words, the second linear portions 95-2 extend from one ends(ends far from the other row) of the plurality of first linear portions95-1 arranged with inclinations in two rows in a direction along theouter peripheral edge of the semiconductor element.

Accordingly, the bent portions 95-3, that is, the parts to which theprotruded connection terminals of the semiconductor element areconnected are alternately provided having different distances from theouter peripheral edge of the semiconductor element.

Accordingly, it is possible to effectively increase the distance betweenadjacent bent portions 95-3, and also to effectively increase the pitchin a direction along the outer peripheral edge of the semiconductorelement of the external connection terminals of the semiconductorelement that are connected to the bent portions 95-3.

Meanwhile, the second linear portions 95-2 extending in the samedirection are arranged so that they are in parallel to each other.

FIGS. 10A and 10B illustrate an arrangement structure of externalconnection terminal pads and protruded external connection terminals ofa semiconductor element to be mounted on a wiring substrate having theabove-described electrode terminal arrangement structure (secondembodiment and third embodiment). FIGS. 10A and 10B each illustrate onecorner portion of a semiconductor element.

In the example shown in FIG. 10A, a plurality of external connectionterminal pads 117 are arranged in two rows along a linear outerperipheral edge of a semiconductor element 100 and in a manner in whichtheir distances from that linear outer peripheral edge are different foreach row.

In each of the external connection terminal pads 117, a protrudedexternal connection terminal 114 is arranged. In other words, thesemiconductor element 100 has two mutually-parallel rows of protrudedexternal connection terminals 114 formed along its outer peripheraledge.

Meanwhile, in the example shown in FIG. 10B, rectangular externalconnection terminal pads 127 extending from an outer peripheral edgeportion of the semiconductor element 110 toward the inside thereof arearranged in rows along a linear outer peripheral edge of thesemiconductor element.

In adjacent rectangular external connection terminal pads 127, protrudedexternal connection terminals 124 are alternately arranged on differentends in the length direction of the rectangular, that is, either an endclose to the linear outer peripheral edge of the semiconductor elementor an end on the side far from the linear outer peripheral edge. Inother words, the semiconductor element 110 also has twomutually-parallel rows of protruded external connection terminals 124formed along its outer peripheral edge.

When mounting a semiconductor element having the above-describedprotruded external connection terminal arrangement on the wiringsubstrate (81 or 91) shown in FIG. 8 or FIG. 9 by means of flip-chipboding, the protruded external connection terminals arranged in two rowsalong a linear outer peripheral edge of the semiconductor element areconnected to the bent portions (85-3 or 95-3) of the electrode terminalsarranged in two rows on the wiring substrate.

At this time, in each of the bent portions in two rows, a protrudedexternal connection terminal is firmly connected and fixed to the bentportion by means of a thickly-disposed (i.e., a large amount of)conductive member. Also, non-uniformity of heights of the protrudedexternal connection terminals, or warpage of the wiring substrate can beabsorbed. Consequently, the semiconductor element and the electrodeterminals on the wiring substrate are connected with high connectionstability (yield) and high connection reliability.

Also, as described above, the bent portions of the electrode terminalsarranged in rows on the wiring substrate, that is, the parts to whichthe external connection terminals are connected are alternately providedbetween the rows with the respective adjacent bent portions havingdifferent distances from the outer peripheral edge of the semiconductorelement.

Accordingly, the distance between the adjacent bent portions is large ineffect, making it possible to effectively increase the pitch of theexternal connection terminals on the semiconductor element that areconnected to the bent portions. As a result, a dielectric strengthvoltage between the external connection terminals can be ensured,enabling the mounting of a semiconductor element including externalconnection terminals in high density by means of flip-chip bonding.

Fourth Embodiment

FIG. 11 shows the configuration of electrode terminals of a wiringsubstrate according to a fourth embodiment. In the Figure, dashed line Bindicates an outer peripheral edge of a semiconductor element mounted ona wiring substrate 131. In other words, the semiconductor element ispositioned on the right side of dashed line B. A dashed line circleindicates a part where a protruded external connection terminal of thesemiconductor element is connected to an electrode terminal on thewiring substrate.

In this fourth embodiment, a plurality of electrode terminals 135arranged on the wiring substrate 131 each include a first linear portion135-1 having a fixed width and second linear portions 135-2A, 135-2Bextending from both ends of the relevant first linear portion 135-1.

A plurality of first linear portions 135-1 are arranged in a directionalong the outer peripheral edge of the semiconductor element, and twosecond linear portions 135-2A, 135-2B are connected to each other viabent portions 135-3A, 135-3B, each constituting an obtuse angle, at bothends of the first linear portion 135-1, and they extend in directionsthat are different from each other. According to this configuration, twobent portions, that is, parts to which protruded external connectionterminals of the semiconductor element are connected are provided forone electrode wiring 135.

At this time, the first linear portions 135-1 arranged along the outerperipheral edge of the semiconductor element have the same length, sothe bent portions 135-3A, 135-3B are arranged in parallel to each otheralong the outer peripheral edge of the semiconductor element, formingrows.

In the Figure, reference numeral 15 denotes a solder resist layer.

FIG. 12 shows an arrangement structure of external connection terminalpads and protruded external connection terminals of a semiconductorelement to be mounted by means of flip-chip bonding on the wiringsubstrate 131 having the above-described electrode terminal arrangementstructure. FIG. 12 also illustrates one corner portion of asemiconductor element. In other words, a plurality of rectangularexternal connection terminal pads 137 extending from the outerperipheral edge portion toward the inside are arranged in a row and inparallel to each other along one linear outer peripheral edge of asemiconductor element 132.

In one rectangular external connection terminal pad 137, two protrudedexternal connection terminals 134A, 134B are aligned in the longitudinaldirection of the rectangle. In other words, the semiconductor element132 also has two rows of mutually-parallel protruded external connectionterminals 134 arranged along one linear peripheral edge thereof.

FIG. 13 shows a state in which the semiconductor element 132 having theabove-described protruded external connection terminal arrangementstructure is mounted by means of flip-chip bonding on the wiringsubstrate 131.

In other words, on one principal surface of the wiring substrate 131,the semiconductor element 132 is mounted by means of a flip-chip(face-down) method, and the protruded external connection terminals 134of the semiconductor element 132 and the corresponding electrodeterminals 135 on the wiring substrate 131 are mechanically andelectrically connected via the conductive member 19.

Here, two protruded external connection terminals 134A, 134B arranged onthe electrode terminal pad 137 of the semiconductor element 132 areconnected via the conductive member 19 to the bent portions 135-3A,135-3B at both ends of the electrode terminal 135-1 on the wiringsubstrate 131.

In other words, the electrode terminal pads 137 of the semiconductorelement 132 are connected at two positions to one electrode terminal135, and the two protruded external connection terminals 134A, 134B arerespectively connected and fixed to the corresponding bent portions bymeans of the thickly-disposed (i.e., a large amount of) conductivemember 19.

Also, at this time, non-uniformity of the heights of the protrudedexternal connection terminals 134 or warpage of the wiring substrate 131is absorbed, and the semiconductor element 132 and the electrodeterminals 135 on the wiring substrate are connected with high connectionstability (yield) and high connection reliability.

In the Figure, reference numeral 20 denotes an underfill material.

Fifth Embodiment

FIG. 14 shows the configuration of electrode terminals of a wiringsubstrate according to a fifth embodiment. In the Figure, dashed line Bindicates an outer peripheral edge of a semiconductor element to bemounted on a wiring substrate 151. In other words, the semiconductorelement is positioned on the right side of dashed line B. Also, a partwhere a protruded external connection terminal of the semiconductorelement is connected to an electrode terminal on the wiring substrate isindicated by a dashed line circle.

In this fifth embodiment, a plurality of electrode terminals 155arranged on the wiring substrate 151 each include a first linear portion155-1 having a fixed width, and second linear portions 155-2A, 155-2Bextending from both ends of the relevant first linear portion 155-1.

The first linear portion 155-1 is inclined relative to a direction alongthe outer peripheral edge of the semiconductor element to be mounted,and a plurality of first linear portions 155-1 are arranged in parallelto each other in a direction along the outer peripheral edge of thesemiconductor element.

Meanwhile, two second linear portions 155-2A and 155-2B are connected toeach other via bent portions 155-3A, 155-3B, each substantiallyconstituting a right angle, at both ends of the first linear portion155-1, and they extend in directions that are opposite to each other.Also, each of a plurality of second linear portions 155-2A and aplurality of second linear portions 155-2B is arranged in parallel in adirection along the outer peripheral edge of the semiconductor element.

In this configuration, also, two bent portions, that is, parts to whichprotruded external connection terminals of the semiconductor element areconnected are provided for one electrode terminal 155. At this time,first linear portions 155-1 adjacent to each other along the outerperipheral edge of the semiconductor element has the same length, so thebent portions 155-3A, 155-3B are arranged in parallel to each otheralong the outer peripheral edge of the semiconductor element, formingrows.

In the Figure, reference numeral 15 denotes a solder resist layer.

FIG. 15 shows an arrangement structure of external connection terminalpads and protruded external connection terminals of a semiconductorelement 152 to be mounted by means of flip-chip bonding on the wiringsubstrate 151 having the above-described electrode terminal arrangementstructure. FIG. 15 also illustrates one corner portion of asemiconductor element.

In other words, rectangular external connection terminal pads 157 arearranged in a row and in parallel to each other along a linear outerperipheral edge of the semiconductor element 152. In each externalconnection terminal pad 157, protruded external connection terminals154A, 154B are aligned substantially along a diagonal line of therectangle. In other words, the semiconductor element 152 also has tworows of substantially-parallel protruded external connection terminals154 arranged along one linear peripheral edge thereof.

FIG. 16 shows a state in which the semiconductor element 152 having theabove-described protruded external connection terminal arrangementstructure is mounted by means of flip-chip bonding on the wiringsubstrate 151.

In other words, on one principal surface of the wiring substrate 151,the semiconductor element 152 is mounted by means of a flip-chip(face-down) method, and the protruded external connection terminals 154of the semiconductor element 152 and the corresponding electrodeterminals 155 on the wiring substrate 151 are mechanically andelectrically connected via the conductive member 19. Here, the protrudedexternal connection terminals 154A, 154B of the semiconductor element152 are connected at the bent portions 155-3A, 155-3B of thecorresponding electrode terminals 155-1 via the conductive member 19.

In other words, one external connection terminal pad 157 of thesemiconductor element 152 is connected at two positions to one electrodeterminal 155 on the wiring substrate, and two protruded externalconnection terminal 154A, 154B are respectively connected and fixed atthe corresponding bent portions to the electrode terminal 155 by meansof the thickly-disposed (i.e., a large amount of) conductive member 19.

Also, at this time, non-uniformity of the heights of the protrudedexternal connection terminals 154, or warpage of the wiring substrate151 is absorbed, and the semiconductor element 152 and the electrodeterminals 155 on the wiring substrate are connected with high connectionstability (yield) and high connection reliability.

In the Figure, reference numeral 20 denotes an underfill material.

1. A wiring substrate comprising a plurality of electrode terminals, towhich external connection terminals of an electronic component arecoupled, arranged in a row on one principal surface thereof, wherein theelectrode terminals each include: a first linear portion; a secondlinear portion extending from an end of the first linear portion in adirection different from a direction of the first linear portion; and abent portion that is a part where the first linear portion and thesecond linear portion are connected.
 2. The wiring substrate accordingto claim 1, wherein the first linear portions of the plurality ofelectrode terminals are arranged in parallel to each other.
 3. Thewiring substrate according to claim 1, wherein the second linearportions of the plurality of electrode terminals are arranged inparallel to each other.
 4. The wiring substrate according to claim 1,wherein the bent portions of the plurality of electrode terminals arearranged in a row.
 5. The wiring substrate according to claim 4,wherein: a plurality of the rows formed by the plurality of electrodeterminals on the principal surface are formed in parallel to each other;and the bent portions of the electrode terminals constituting one of therows and the bent portions of the electrode terminals constitutinganother of the rows are shifted from each other in a direction of therows being formed.
 6. The wiring substrate according to claim 1, whereinthe plurality of electrode terminals have the bent portions arranged ina plurality of rows, and the plurality of rows are in parallel to eachother.
 7. The wiring substrate according to claim 1, wherein theplurality of electrode terminals have the bent portions at both ends ofthe respective first linear portions.
 8. The wiring substrate accordingto claim 7, wherein the bent portions arranged at one of the ends of thefirst linear portions, and the bent portions arranged at the other ofthe ends of the first linear portions are aligned in a directionperpendicular to a direction of the electrode terminals being arranged.9. The wiring substrate according to claim 7, wherein the bent portionsarranged at one of the ends of the first linear portions, and the bentportions arranged at the other of the ends of the first linear portionsare shifted from each other in a direction of the electrode terminalsbeing arranged.
 10. The wiring substrate according to claim 1, whereineach of the second linear portions extends from an end of acorresponding one of the first linear portions at an acute anglerelative to the corresponding first linear portion.
 11. An electronicdevice comprising: a wiring substrate including a plurality of electrodeterminals arranged in a row on one principal surface thereof; and anelectronic component mounted on the plurality of electrode terminals viaa conductive member, wherein: the electrode terminals each includes afirst linear portion, a second linear portion extending from an end ofthe first linear portion in a direction different from a direction ofthe first linear portion, and a bent portion that is a part where thefirst linear portion and the second linear portion are connected; andexternal connection terminals of the electronic component are coupled tothe bent portions of the electrode terminals via the conductive member.12. The electronic device according to claim 11, wherein the externalconnection terminals of the electronic component each have a protrudedportion.
 13. The electronic device according to claim 11, wherein theexternal connection terminals of the electronic component are coupled tothe electrode terminals on the wiring substrate, the external connectionterminals of the electronic component forming a plurality of rows thatare in parallel to each other.
 14. The electronic device according toclaim 11, wherein: the bent portions of the electrode terminals on thewiring substrate are arranged so that the bent portions conform to theconfiguration of the external connection terminals of the electroniccomponent; and the external connection terminals of the electroniccomponent are coupled to the bent portions of the electrode terminalsvia the conductive member.
 15. The electronic device according to claim11, wherein the conductive member includes a material containing solder.